<template>
    <div class="list">
        <button 
            class="item"
            v-for="(item) of letters"
            :key="item"
            :ref="item"
            @click="handleLetterClick"            
        >
        <!-- 
            @touchstart.prevent="handleTouchStart"
            @touchmove="handleTouchMove"
            @touchend="handleTouchEnd"
        -->
            {{item}}
        </button>
    </div>
</template>
<script>
export default {
    name:'CityAlphabet',
    data(){
        return{
            touchStatus:false,
            startY:0,
            timer:null
        }
    },
    updated(){
        this.startY = this.$refs['A'][0].offsetTop
    },
    props:{
        cities:Object
    },
    computed:{
        letters(){
            const letters = []
            for(let i in this.cities){
                letters.push(i)
            }
            return letters
        }
    },
    methods:{
        handleLetterClick(e){
            this.$emit('change', e.target.innerText)
        },
        // handleTouchStart(){
        //     this.touchStatus = true
        // },
        // handleTouchMove(e){
        //     if(this.touchStatus){
        //         if(this.timer){
        //             clearTimeout(this.timer)
        //         }
        //         this.timer = setTimeout(() => {
        //             const touchY = e.touches[0].clientY - 79
        //             const index = Math.floor((touchY - this.startY)/20)
        //             if(index >= 0 && index < this.letters.length){
        //                 this.$emit('change', this.letters[index])
        //             }
        //         }, 16)
        //     }
        // },
        // handleTouchEnd(){
        //     this.touchStatus = false
        // }

    }
}
</script>
<style lang="stylus" scoped>
    @import '~@/assets/styles/variables.styl';
    .list
        display:flex
        flex-direction:column
        justify-content:center
        position:absolute
        right:0
        top: 1.58rem
        bottom:0
        width:.4rem
        .item
            line-height: .4rem
            text-align:center
            color:$bgColor

</style>